My application is crashing when one of the views is purged from memory because of low-memory condition. At least this is what I understand from the crashlog. It happens on numerous screens but only when opening a Facebook dialog (using the Facebook SDK). Basically, looks like the system sometimes runs out of memory when we need to present a Facebook dialog (e.g. to let user post something on the Facebook timeline).
Date/Time: 2012-03-14 19:47:33.819 +0000
OS Version: iPhone OS 5.1 (9B176)
Report Version: 104
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x30000008
Crashed Thread: 0
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libobjc.A.dylib 0x30f2bf78 objc_msgSend + 16
1 MyApp 0x00003c0e -LTBaseViewController viewDidUnload (LTBaseViewController.m:145)
2 MyApp 0x00004ea2 -LTBaseTableViewController viewDidUnload (LTBaseTableViewController.m:90)
3 UIKit 0x33766bd8 -[UIViewController unloadViewForced:] + 244
4 UIKit 0x338ae492 -[UIViewController purgeMemoryForReason:] + 58
5 Foundation 0x3071a4f8 __57-NSNotificationCenter addObserver:selector:name:object:_block_invoke_0 + 12
6 CoreFoundation 0x30e95540 ___CFXNotificationPost_block_invoke_0 + 64
7 CoreFoundation 0x30e21090 _CFXNotificationPost + 1400
8 Foundation 0x3068e3e4 -NSNotificationCenter postNotificationName:object:userInfo: + 60
9 Foundation 0x3068fc14 -NSNotificationCenter postNotificationName:object: + 24
10 UIKit 0x3387926a -UIApplication _performMemoryWarning + 74
11 UIKit 0x33879364 -UIApplication _receivedMemoryNotification + 168
12 libdispatch.dylib 0x36a12252 _dispatch_source_invoke + 510
13 libdispatch.dylib 0x36a0fb1e _dispatch_queue_invoke$VARIANT$up + 42
14 libdispatch.dylib 0x36a0fe64 _dispatch_main_queue_callback_4CF$VARIANT$up + 152
15 CoreFoundation 0x30e9c2a6 __CFRunLoopRun + 1262
16 CoreFoundation 0x30e1f49e CFRunLoopRunSpecific + 294
17 CoreFoundation 0x30e1f366 CFRunLoopRunInMode + 98
18 GraphicsServices 0x33fb6432 GSEventRunModal + 130
19 UIKit 0x336f5e76 UIApplicationMain + 1074
20 MyApp 0x00004818 main (main.m:16)
21 MyApp 0x000023b4 0x1000 + 5044
I checked and there are almost no memory leaks, e.g. when testing the app for an hour the total memory leaked was around 2-3Kb caused by some string-copying libraries. So I don't believe this is caused by the application. I guess that when the phone is not restarted for some time there are applications running in the background and when using Facebook SDK the memory becomes a problem and the system tries to recover the memory from random applications, including my application.
My question is, how can I prevent this crash from happening? How should I handle unloadViewForced on a view controller to make the app more robust in low-memory conditions? And lastly, am I right that this crashlog suggests the crash occurred because the system tried to free memory and my application didn't handle it properly?
Any help greatly appreciated.
What is most likely happening is that one of the objects being referred to and probably being released by LTBaseViewController viewDidUnload method is being doubly released. In fact, since the backtrace indicates that the crash is happing on line 145 of LTBaseViewController.m you should be able to quickly see which object is the culprit.
Related
I'm running my ios app in ipad 1, the following crash happen sometime while app is running, i don't know where the crash happen. This mostly happen in ios 5.1.1 . Here the crash log,
Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0xf0000008
Crashed Thread: 0
Thread 0 name: Dispatch queue: com.apple.main-thread
Thread 0 Crashed:
0 libobjc.A.dylib 0x3387ef78 objc_msgSend + 16
1 UIKit 0x333ffa3a -[UIViewController unloadViewForced:] + 254
2 UIKit 0x335473a6 -[UIViewController purgeMemoryForReason:] + 58
3 Foundation 0x3507a4f8 __57-[NSNotificationCenter addObserver:selector:name:object:]_block_invoke_0 + 12
4 CoreFoundation 0x35c2c540 ___CFXNotificationPost_block_invoke_0 + 64
5 CoreFoundation 0x35bb8090 _CFXNotificationPost + 1400
6 Foundation 0x34fee3e4 -[NSNotificationCenter postNotificationName:object:userInfo:] + 60
7 Foundation 0x34fefc14 -[NSNotificationCenter postNotificationName:object:] + 24
8 UIKit 0x335120e6 -[UIApplication _performMemoryWarning] + 74
9 UIKit 0x335121e0 -[UIApplication _receivedMemoryNotification] + 168
10 libdispatch.dylib 0x33ffb252 _dispatch_source_invoke + 510
11 libdispatch.dylib 0x33ff8b1e _dispatch_queue_invoke$VARIANT$up + 42
12 libdispatch.dylib 0x33ff8e64 _dispatch_main_queue_callback_4CF$VARIANT$up + 152
13 CoreFoundation 0x35c332a6 __CFRunLoopRun + 1262
14 CoreFoundation 0x35bb649e CFRunLoopRunSpecific + 294
15 CoreFoundation 0x35bb6366 CFRunLoopRunInMode + 98
16 GraphicsServices 0x33951432 GSEventRunModal + 130
17 UIKit 0x3338ecce UIApplicationMain + 1074
18 MY Game 0x00079a90 0x75000 + 19088
19 MY Game 0x00079a50 0x75000 + 19024
As i understand from crash log, crash not happen due to my code. It's due low memory. Is that correct? How to find where the crash happen? Any suggestions.
As i understand from crash log, crash not happen due to my code. It's due low memory. Is that correct?
No, that's not correct.
Low memory is being reported, but your view controller is not responding properly. The most common cause of this is a retain cycle - see UIViewController purgeMemoryForReason: Crashing on iOS 5. In that answer, the retain cycle is in SVPullToRefresh , but yours could be elsewhere. The most common cause of retain cycles is not setting a delegate property to weak.
Once you figure out where the issue is, you can set breakpoints in viewDidUnload and ``didReceiveMemoryWarning`, simulate a memory warning, and step through your code to find the error.
Symbolication
Additionally, this crash report isn't symbolicated. Typically you'll want to symbolicate your crash report first. For example, see these lines:
18 MY Game 0x00079a90 0x75000 + 19088
19 MY Game 0x00079a50 0x75000 + 19024
In this case, as pointed out by Kerni, those two will just show start and main, so they won't help you in this instance. But generally, you should symbolicate your crash reports. (Search for "Xccode symbolicate crash logs" if you don't know how to do this.)
I have been getting rather strange crash reports from my live app with stack traces like the following:
Thread 0: Crashed: com.apple.main-thread
0 libobjc.A.dylib 0x38af7942 realizeClass(objc_class*) + 117
1 libsystem_malloc.dylib 0x390dbef5 szone_malloc_should_clear + 1376
2 libobjc.A.dylib 0x38af976f lookUpImpOrForward + 74
3 libobjc.A.dylib 0x38af1feb _class_lookupMethodAndLoadCache3 + 34
4 libobjc.A.dylib 0x38af1db9 _objc_msgSend_uncached + 24
5 UIKit 0x30e571bf __57-[_UIDelayedPresentationContext beginDelayedPresentation]_block_invoke + 26
6 libdispatch.dylib 0x38fd9d07 _dispatch_client_callout + 22
7 libdispatch.dylib 0x38fe2803 _dispatch_source_invoke$VARIANT$mp + 262
8 libdispatch.dylib 0x38fe073d _dispatch_main_queue_callback_4CF$VARIANT$mp + 188
9 CoreFoundation 0x2e3ef819 __CFRUNLOOP_IS_SERVICING_THE_MAIN_DISPATCH_QUEUE__ + 8
10 CoreFoundation 0x2e3ee0ed __CFRunLoopRun + 1300
11 CoreFoundation 0x2e358c27 CFRunLoopRunSpecific + 522
12 CoreFoundation 0x2e358a0b CFRunLoopRunInMode + 106
13 GraphicsServices 0x3302c283 GSEventRunModal + 138
14 UIKit 0x30bfc049 UIApplicationMain + 1136
This is rather mysterious because neither the main thread nor any of the other live threads in the reports seem to imply that this is caused by my code, though of course I am skeptical of this.
This seems to be a rather common crash according to the number of reports I receive from Crashlytics, yet I have not been able to reproduce it on my own devices. I suspect this is probably related to some memory management issues because the various crashes always end up being some bad pointers being sent messages.
This always happens on this thread and following the -[_UIDelayedPresentationContext beginDelayedPresentation]_block_invoke call. This is obviously a private class being referenced from within some Apple framework, however I am at a loss to figure out exactly which one could be calling this.
The app is an educational game and I suspect this could be related to the GameKit API (particularly the Game Center authentication dialogs).
All of these crashes have been happening exclusively on iOS 7 and on iPad only. The app is universal so it is interesting to see that iPhone users seem to be unaffected.
Does anybody have any previous experience with these private classes that could give me some hints?
I'm using the TestFlight SDK and have received several crash reports identical to this one. However, I'm having trouble understanding it, and what the underlying cause of the crash is from the reports?
Exception
SIGSEGV
2 libsystem_c.dylib 0x32862e92 _sigtramp + 42
3 Foundation 0x33750d1c -[NSError dealloc] + 60...
Exception reason
SIGSEGV
Stacktrace
0 MyAppName 0x0013faba testflight_backtrace + 382
1 MyAppName 0x00140708 TFSignalHandler + 264
2 libsystem_c.dylib 0x32862e92 _sigtramp + 42
3 Foundation 0x33750d1c -[NSError dealloc] + 60
4 libobjc.A.dylib 0x39230488 _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 168
5 CoreFoundation 0x31de9440 _CFAutoreleasePoolPop + 16
6 Foundation 0x33751f7a -[NSAutoreleasePool drain] + 122
7 CoreData 0x35e0a4b2 -[NSManagedObjectContext save:] + 1210
8 MyAppName 0x000b7168 MR_swapMethodsFromClass + 18076
9 CoreData 0x35e0dbc0 developerSubmittedBlockToNSManagedObjectContextPerform + 88
10 libdispatch.dylib 0x335974b6 _dispatch_client_callout + 22
11 libdispatch.dylib 0x33598dca _dispatch_main_queue_callback_4CF$VARIANT$up + 226
12 CoreFoundation 0x31e79f3a __CFRunLoopRun + 1290
13 CoreFoundation 0x31decebc CFRunLoopRunSpecific + 356
14 CoreFoundation 0x31decd48 CFRunLoopRunInMode + 104
15 GraphicsServices 0x36e092ea GSEventRunModal + 74
16 UIKit 0x320db2f8 UIApplicationMain + 1120
17 MyAppName 0x00099122 main (main.m:17)
18 MyAppName 0x000990d7 start + 39
Additional details:
Users report this crash happens 1-2 seconds after the app starts
The app uses Core Data and MagicalRecord (which is where the MR_swapMethodsFromClass method comes from)
I can't reproduce this issue on any test devices when running from Xcode (iPhone 3GS, iPhone 4, or iPhone 5) running various iOS versions (iOS 5.1, 6.0, 6.1)
EDIT
Still working on solving this issue... I've been able to recreate it (but not with a debugger attached).
Here's the strangest part-- if a user has an older version of the app and installs an update (distributed via Test Flight), they get this error.
However, if they first delete the old app and install the update, the error doesn't occur.
Let's walk through it:
0 MyAppName 0x0013faba testflight_backtrace + 382
1 MyAppName 0x00140708 TFSignalHandler + 264
That's TestFlight. This is after the crash has happened, so it's certainly not the cause.
2 libsystem_c.dylib 0x32862e92 _sigtramp + 42
This is the point at which we caught the crash. "sigtramp" is the signal "trampoline." That's a fancy way of saying "I caught a signal (crash) and now I'm going to bounce to somewhere else in the code."
3 Foundation 0x33750d1c -[NSError dealloc] + 60
Ah. This is important. We crashed while deallocating an NSError. That means the NSError was over-released or under-retained.
4 libobjc.A.dylib 0x39230488 _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 168
5 CoreFoundation 0x31de9440 _CFAutoreleasePoolPop + 16
6 Foundation 0x33751f7a -[NSAutoreleasePool drain] + 122
Sad… it manifested while draining the autorelease pool. That means the actual bug could be a long way from here. But at least we know the type of the object. NSZombies could be of use to try to find the specific object.
7 CoreData 0x35e0a4b2 -[NSManagedObjectContext save:] + 1210
And the autorelease pool was draining during a MOC save. That suggests it's probably related to your Core Data code. It's at least where you'd look first.
The things to remember are:
The bug is almost certainly in your code.
If it's not in your code, it's probably in Magical Record
Do not assume it is in Core Data. That is the least likely place for the bug given this stack.
Here's the strangest part-- if a user has an older version of the app and installs an update (distributed via Test Flight), they get this error.
However, if they first delete the old app and install the update, the error doesn't occur.
Probably in your upgrade code then. Most likely in the Core Data migration stuff. Audit every use of NSError in that area of code. Eliminate all compiler and analyzer warnings. And try NSZombies if its reproducible.
You should try to add a model version to your data model. It worked for me, i had a similar Magical-Record-related issue.
In one of our iPhone apps, we have gotten a few Crashlytics crashes that we have, so far, been unable to reproduce. However, on closer inspection, I noticed a bit of a trend...
Crash 1: -[UINavigationTransitionView _notifyDelegateTransitionDidStopWithContext:]
Free RAM: 10%
Crash 2: -[UINavigationTransitionView _notifyDelegateTransitionDidStopWithContext:]
Free RAM: 8%
Crash 3: HostBase::lock()
Free RAM: 8%
Crash 4:-[UINavigationTransitionView _notifyDelegateTransitionDidStopWithContext:]
Free RAM: 22%
Does the amount of free RAM mean anything? Can we be sure that these are actual crashes and not our app getting killed by the OS due to low memory? Does Crashlytics send crash reports if the app crashes while in the background?
Added a couple stack traces...
Exception Type: SIGSEGV, Nav Crashes
0 libobjc.A.dylib
objc_msgSend + 15
1 UIKit ✭
-[UINavigationTransitionView _notifyDelegateTransitionDidStopWithContext:] + 274
2 UIKit
-[UIViewAnimationState sendDelegateAnimationDidStop:finished:] + 158
3 UIKit
-[UIViewAnimationState animationDidStop:finished:] + 50
4 QuartzCore
CA::Layer::run_animation_callbacks(void*) + 208
5 libdispatch.dylib
_dispatch_client_callout + 22
6 libdispatch.dylib
_dispatch_main_queue_callback_4CF$VARIANT$mp + 224
7 CoreFoundation
__CFRunLoopRun + 1290
8 CoreFoundation
CFRunLoopRunSpecific + 356
9 CoreFoundation
CFRunLoopRunInMode + 104
10 GraphicsServices
GSEventRunModal + 74
11 UIKit
UIApplicationMain + 1120
Exception Type: SIGSEGV, HostLock crash
0 libobjc.A.dylib
objc_msgSend + 15
1 CFNetwork ✭
HostBase::lock() + 14
2 CFNetwork
DispatchHost::performInvocation(void const*) + 12
3 CFNetwork
__setupTCPConnection_block_invoke_2 + 290
4
...
libsystem_network.dylib
__tcp_connection_notify_complete_block_invoke_1 + 18
7 libsystem_c.dylib
_pthread_wqthread + 294
8% memory can be a lot, I highly doubt that this is an issue. I don't know if they send crashes while running in the background, you have to ask them directly since their SDK is not open source.
Both exception stack traces you added hint at a memory problem.
The first one looks like it tries to call a delegate at the end of an animation of an object, which does not exist any more.
The second one looks like a similar problem, where the completion block is accessing an object that is gone. So you might check your blocks for such patterns.
An iPhone app is crashing on the device but not on the simulator. So I'm trying to learn how to interpret the crash log. I read lots of forum posts saying that the symbolicated crash log shows a back trace that gives the method and line number of the calls leading to the crash but I don't see anything useful. Maybe I'm not looking at the symbolicated crash log. Here is the beginning of what I see:
Incident Identifier: 432A8974-1661-409F-B5A6-970148550A46
CrashReporter Key: db93147c0a70a5f4c60dc92f826e72d5a74477c8
Hardware Model: iPhone3,3
Process: Darken [57959]
Path: /var/mobile/Applications/CB27C10F-CD3B-4148-8321-2C251888B27B/Darken.app/Darken
Identifier: Darken
Version: ??? (???)
Code Type: ARM (Native)
Parent Process: launchd [1]
Date/Time: 2012-02-25 10:43:47.753 -0500
OS Version: iPhone OS 4.2.10 (8E600)
Report Version: 104
Exception Type: EXC_BAD_ACCESS (SIGBUS)
Exception Codes: KERN_PROTECTION_FAILURE at 0x00000008
Crashed Thread: 0
Thread 0 Crashed:
0 libobjc.A.dylib 0x32716464 objc_msgSend + 16
1 UIKit 0x3245e6fe -[UIScrollView(UIScrollViewInternal) _scrollViewAnimationEnded] + 90
2 CoreFoundation 0x32071bb8 -[NSObject(NSObject) performSelector:withObject:] + 16
3 UIKit 0x3245e5b8 -[UIAnimator stopAnimation:] + 276
4 UIKit 0x323efbf2 -[UIAnimator(Static) _advance:] + 214
5 UIKit 0x323efb0e LCDHeartbeatCallback + 10
6 GraphicsServices 0x35474362 HeartbeatVBLCallback + 86
7 IOMobileFramebuffer 0x34739bf4 IOMobileFramebufferVsyncNotifyFunc + 68
8 IOKit 0x348e5e64 IODispatchCalloutFromCFMessage + 192
9 CoreFoundation 0x32070be0 __CFMachPortPerform + 204
10 CoreFoundation 0x320686f8 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 20
11 CoreFoundation 0x320686bc __CFRunLoopDoSource1 + 160
12 CoreFoundation 0x3205af76 __CFRunLoopRun + 514
13 CoreFoundation 0x3205ac80 CFRunLoopRunSpecific + 224
14 CoreFoundation 0x3205ab88 CFRunLoopRunInMode + 52
15 GraphicsServices 0x354724a4 GSEventRunModal + 108
16 GraphicsServices 0x35472550 GSEventRun + 56
17 UIKit 0x323c7d1a -[UIApplication _run] + 406
18 UIKit 0x323c5884 UIApplicationMain + 664
19 Darken 0x000029d6 0x1000 + 6614
20 Darken 0x00002998 0x1000 + 6552
... Threads other than 0 listed here
Is anything here useful for finding out which line of my code led to the crash? Darken is the name of the application -- I already knew that. The only method name I recognize is UIApplicationMain but the crash didn't happen when the app was first launched -- I was running it about a minute and doing dozens of functions before the crash.
You may want to try and set NSZombieEnabled to YES in your project and let it crash with your device running in debug. It should stop at the line of code causing your crash. Your error looks like it is an EXC_BAD_ACCESS which usually means you were trying to access some deallocated memory.
You won't get a line number from a crash dump (unless you compiled your app with -g and run in GDB, but I doubt it since you don't seem to know what these are at all).
You ARE looking at the symbolicated crash dump: you DO have the names of the functions in the call stack. The crash occurs in the last called (topmost) function, which is objc_msgSend. That means you're not properly balancing your alloc/retain/copy methods with autorelease/release, and the messenger function tries to access already freed/corrupted/nonexistent memory, hence the crash (EXC_BAD_ACCESS is similar to a segfault, in fact you'll get one of these when you make such a mistake).
So my advice is, triple check your code for method calls modifying the reference count.